CD8⁺ cells regulate the T helper-17 response in an experimental murine model of Sjögren syndrome.

This study investigated the regulatory function of CD8⁺ cells in T helper-17 (Th17) cell-mediated corneal epithelial barrier disruption that develops in a murine desiccating stress (DS) model that resembles Sjögren syndrome. CD8⁺ cell depletion promoted generation of interleukin-17A (IL-17A)-producing CD4⁺ T cells via activation of dendritic cells in both the ocular surface and draining cervical lymph nodes in C57BL/6 mice subjected to DS. T-cell-deficient nude recipient mice receiving adoptively transferred CD4⁺ T cells from CD8⁺ cell-depleted donors exposed to DS displayed increased CD4⁺ T-cell infiltration and elevated IL-17A and CC-chemokine attractant ligand 20 levels in the ocular surface, which was associated with greater corneal barrier disruption. Enhanced DS-specific corneal barrier disruption in CD8-depleted donor mice correlated with a Th17-mediated expression of matrix metalloproteinases (MMP-3 and MMP-9) in the recipient corneal epithelium. Co-transfer of CD8⁺CD103⁺ regulatory T cells did not affect the ability of DS-specific pathogenic CD4⁺ T cells to infiltrate and cause ocular surface disease in the nude recipients, showing that CD8⁺ cells regulate the efferent arm of DS-induced immune response. In summary, CD8⁺ regulatory cells suppress generation of a pathogenic Th17 response that has a pivotal role in DS-induced disruption of corneal barrier function.

Potential autocrine regulation of interleukin-33/ST2 signaling of dendritic cells in allergic inflammation.

This study identified a novel phenomenon that dendritic cells (DCs) produced interleukin (IL)-33 via Toll-like receptor (TLR)-mediated innate pathway. Mouse bone marrow-derived DCs were treated with or without microbial pathogens or recombinant murine IL-33. IL-33 mRNA and protein were found to be expressed by DCs and largely induced by several microbial pathogens, highly by lipopolysaccharide (LPS) and flagellin. Using two mouse models of topical challenge by LPS and flagellin and experimental allergic conjunctivitis, IL-33-producing DCs were observed in ocular mucosal surface and the draining cervical lymph nodes in vivo. The increased expression levels of myeloid differentiation primary-response protein 88 (MyD88), nuclear factor (NF)-κB1, NF-κB2, and RelA accompanied by NF-κB p65 nuclear translocation were observed in DCs exposed to flagellin. IL-33 induction by flagellin was significantly blocked by TLR5 antibody or NF-κB inhibitor quinazoline and diminished in DCs from MyD88 knockout mice. IL-33 stimulated the expression of DC maturation markers, CD40 and CD80, and proallergic cytokines and chemokines, OX40L, IL-4, IL-5, IL-13, CCL17 (C-C motif chemokine ligand 17), TNF-α (tumor necrosis factor-α), and IL-1ß. This stimulatory effect of IL-33 in DCs was significantly blocked by ST2 antibody or soluble ST2. Our findings demonstrate that DCs produce IL-33 via TLR/NF-κB signaling pathways, suggesting a molecular mechanism by which local allergic inflammatory response may be amplified by DC-produced IL-33 through potential autocrine regulation.

Health department clinics as pediatric immunization providers: a national survey.

OBJECTIVE: To describe a national sample of health department immunization clinics in terms of populations served, patient volume trends, services offered, and immunization practices. METHODS: Telephone survey conducted with health departments sampled from a national database, using probability proportional to population size. RESULTS: All (100%) 166 sampled and eligible clinics completed the survey. The majority of pediatric patients were uninsured (42%) or enrolled in Medicaid (34%). Most children (69%) and adolescents (70%) were referred to the health department, with only 12% using these clinics as a medical home. A number of clinics (72%) reported recent increases in adolescents served. Less than 25% of clinics offered comprehensive care, 47% conducted semiannual coverage assessments, and 76% and 38% operated recall systems for children and adolescents. Storage of records in an electronic database was common (83%). CONCLUSIONS: Although the majority of these clinics do not provide comprehensive care, they continue to serve vulnerable children, including adolescents, Medicaid enrollees, and the uninsured, and may represent the main contact with the healthcare system for such patients. Because assuring the immunization of these children is essential to their health and the health of our nation as a whole, this immunization safety net must be preserved. Experience implementing key recommendations such as coverage assessment and feedback as well as reminder or recall may enable health department staff to assist private provider colleagues. Further research is needed to investigate how patient populations, services offered, and immunization practices vary by different clinic characteristics.